CVE-2026-33636

HIGHNVD 7.67.6
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This high-severity CVE scores 7.6 under NVD CVSS v3. EPSS exploit probability: 0.4% (28th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Trending — 3 sources updated this week
7.6EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.6Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. In versions 1.6.36 through 1.6.55, an out-of-bounds read and write exists in libpng's ARM/AArch64 Neon-optimized palette expansion path. When expanding 8-bit paletted rows to RGB or RGBA, the Neon loop processes a final partial chunk without verifying that enough input pixels remain. Because the implementation works backward from the end of the row, the final iteration dereferences pointers before the start of the row buffer (OOB read) and writes expanded pixel data to the same underflowed positions (OOB write). This is reachable via normal decoding of attacker-controlled PNG input if Neon is enabled. Version 1.6.56 fixes the issue.

CVSS v3
7.6
EG Score
7.6HIGHmedium confidence
EG Risk
34
EG Risk 34/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity76% × 45%
The EG Score, 7.6 of 10.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
28th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

March 26, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Jun 12, 2026
Patch available. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)

Out-of-bounds read/write in the palette expansion on ARM Neon · Advisory · pnggroup/libpng · GitHub

https://github.com/pnggroup/libpng/security/advisories/GHSA-wjr5-c57x-95m2
GitHub commit

commit aba9f18eba87 (pnggroup/libpng)

Fix landed in pnggroup/libpng commit aba9f18eba87 — awaiting tagged release

https://github.com/pnggroup/libpng/commit/aba9f18eba870d14fb52c5ba5d73451349e339c3
GitHub commit

commit 7734cda20cf1 (pnggroup/libpng)

Fix landed in pnggroup/libpng commit 7734cda20cf1 — awaiting tagged release

https://github.com/pnggroup/libpng/commit/7734cda20cf1236aef60f3bbd2267c97bbb40869

Vendor Advisories for CVE-2026-33636(20)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(30)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatdiscovery/discovery-ui-rhel9:17827565412026-06-29redhat
redhatlibpng-2:1.6.40-11.el10_2.12026-06-23redhat
redhatlibpng-2:1.6.37-15.el9_8.22026-06-23redhat
redhatrhaiis/model-opt-cuda-rhel9:17806819842026-06-10redhat
redhatlibpng-2:1.6.37-12.el9_2.32026-05-14redhat
redhatlibpng-2:1.6.37-12.el9_4.32026-05-14redhat
redhatlibpng-2:1.6.40-8.el10_0.32026-05-14redhat
redhatlibpng-2:1.6.37-12.el9_0.32026-05-14redhat
redhatlibpng-2:1.6.37-12.el9_6.32026-05-14redhat
redhatthunderbird-0:140.9.1-1.el8_62026-05-11redhat
redhatlibpng-2:1.6.37-12.el9_7.32026-05-07redhat
redhatlibpng-2:1.6.40-8.el10_1.32026-05-07redhat
redhatthunderbird-0:140.9.1-1.el8_82026-05-06redhat
redhatthunderbird-0:140.9.1-1.el8_42026-05-06redhat
redhatfirefox-0:140.9.1-2.el7_92026-05-06redhat
redhatfirefox-0:140.9.1-1.el9_22026-05-06redhat
redhatfirefox-0:140.9.1-1.el9_42026-05-05redhat
redhatfirefox-0:140.9.1-1.el10_02026-05-05redhat
redhatfirefox-0:140.9.1-1.el8_82026-05-05redhat
redhatfirefox-0:140.9.1-1.el9_62026-05-05redhat
redhatfirefox-0:140.9.1-1.el9_02026-05-05redhat
redhatfirefox-0:140.9.1-1.el8_42026-05-05redhat
redhatfirefox-0:140.9.1-1.el8_62026-05-05redhat
redhatthunderbird-0:140.9.1-1.el9_22026-05-04redhat
redhatthunderbird-0:140.9.1-1.el9_42026-05-04redhat
redhatthunderbird-0:140.9.1-1.el9_62026-05-04redhat
redhatthunderbird-0:140.9.1-1.el9_02026-04-30redhat
redhatthunderbird-0:140.9.1-1.el10_02026-04-29redhat
redhatfirefox-0:140.9.1-1.el8_22026-04-29redhat
redhatjava-1.8.0-openjdk-1:1.8.0.492.b09-1.el92026-04-24redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(9 across 9 ecosystems)
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
libpng—
  • 1.6.36 up to 1.6.56-r0: fixed in 1.6.56-r0
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
libpng—
  • 1.6.36 up to 1.6.56-r0: fixed in 1.6.56-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
libpng—
  • 1.6.36 up to 1.6.56-r0: fixed in 1.6.56-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
libpng—
  • 1.6.36 up to 1.6.56-r0: fixed in 1.6.56-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
libpng—
  • 1.6.36 up to 1.6.56-r0: fixed in 1.6.56-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
libpng1.61.6.37-3, 1.6.37-3+deb11u1, 1.6.37-3+deb11u2
  • every version up to 1.6.37-3+deb11u3: fixed in 1.6.37-3+deb11u3
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
libpng1.61.6.39-2, 1.6.39-2+deb12u1, 1.6.39-2+deb12u2, 1.6.39-2+deb12u3
  • every version up to 1.6.39-2+deb12u4: fixed in 1.6.39-2+deb12u4
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libpng1.61.6.48-1, 1.6.48-1+deb13u1, 1.6.48-1+deb13u2, 1.6.48-1+deb13u3
  • every version up to 1.6.48-1+deb13u4: fixed in 1.6.48-1+deb13u4
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libpng1.61.6.48-1 ... 1.6.55-1 (9 versions)
  • every version up to 1.6.56-1: fixed in 1.6.56-1
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(11)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 12× in last 7d / 30× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 97 of 218 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 3 repeat rows among the latest 100 are merged into the row they repeat. The 121 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  2. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  3. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  4. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  5. 2026-10-12 16:13 UTCEG score recompute
  6. 2026-10-11 19:55 UTCEG score recompute
  7. 2026-10-11 17:08 UTCEG score recompute
  8. 2026-10-11 14:35 UTCEG score recompute
  9. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  10. 2026-10-11 04:31 UTCOSV refresh
  11. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  12. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  13. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  14. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  15. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  16. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  18. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  19. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  20. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  21. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  22. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  23. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  24. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  25. 2026-09-21 16:19 UTCOSV refresh
Show 72 more
  1. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  2. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  3. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  4. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  5. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  6. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  7. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  8. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  9. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  10. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  11. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  12. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  13. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  14. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  15. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  16. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  17. 2026-09-02 13:26 UTCOSV refresh
  18. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  19. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  20. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  21. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  22. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  23. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  24. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  25. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  26. 2026-08-24 14:17 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  27. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  28. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  29. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  30. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  31. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  32. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  33. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  34. 2026-08-16 10:07 UTCEG score recompute
  35. 2026-08-16 10:07 UTCVendor advisory
  36. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  37. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  38. 2026-08-14 19:26 UTCVendor advisory
  39. 2026-08-14 06:25 UTCEG score recompute
  40. 2026-08-14 06:25 UTCVendor advisory
  41. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  42. 2026-08-12 20:42 UTCEG score recompute
  43. 2026-08-12 20:42 UTCVendor advisory
  44. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  45. 2026-08-11 20:49 UTCEG score recompute
  46. 2026-08-11 20:49 UTCVendor advisory
  47. 2026-08-11 03:51 UTCEG score recompute
  48. 2026-08-11 03:51 UTCVendor advisory
  49. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  50. 2026-08-10 04:48 UTCVendor advisory
  51. 2026-08-09 17:23 UTCEG score recompute
  52. 2026-08-09 17:23 UTCVendor advisory
  53. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  54. 2026-08-09 05:58 UTCEG score recompute
  55. 2026-08-09 05:58 UTCVendor advisory
  56. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  57. 2026-08-08 03:48 UTCEG score recompute
  58. 2026-08-08 03:48 UTCVendor advisory
  59. 2026-08-07 16:24 UTCVendor advisory
  60. 2026-08-06 18:46 UTCEG score recompute
  61. 2026-08-06 18:46 UTCVendor advisory
  62. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  63. 2026-08-06 00:52 UTCEG score recompute
  64. 2026-08-06 00:52 UTCVendor advisory
  65. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  66. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  67. 2026-08-04 10:38 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  68. 2026-08-03 23:17 UTCEG score recompute
  69. 2026-08-03 23:17 UTCVendor advisory
  70. 2026-08-03 10:36 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  71. 2026-08-03 03:00 UTCVendor advisory
  72. 2026-08-02 15:22 UTCEG score recompute

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-33636?
CVE-2026-33636 is a high-severity vulnerability; its CVE record was published on March 26, 2026. LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. In versions 1.6.36 through 1.6.55, an out-of-bounds read and write exists in libpng's ARM/AArch64 Neon-optimized palette expansion path. When expanding 8-bit…
When was the CVE record for CVE-2026-33636 published?
The CVE record for CVE-2026-33636 was published on March 26, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of June 17, 2026; the record at its source may have been updated since.
Is CVE-2026-33636 actively exploited?
CVE-2026-33636 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (28th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-33636?
CVE-2026-33636 has a CVSS v3 base score of 7.6 (NVD).
How do I remediate CVE-2026-33636?
A fix for CVE-2026-33636 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-33636 are linked in the Vendor Advisories panel on this page.

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